Added galaxy nexus specific settings

First addition is gamma color hack

Change-Id: I199dc40334b4219bb4d3209360faeef2d66b6da1

7 files changed, 704 insertions, 0 deletions

diff --git a/GNexusParts/src/com/cyanogenmod/settings/device/DeviceSettings.java b/GNexusParts/src/com/cyanogenmod/settings/device/DeviceSettings.java
new file mode 100644
index 0000000..f2f9a83
--- /dev/null
+++ b/GNexusParts/src/com/cyanogenmod/settings/device/DeviceSettings.java
@@ -0,0 +1,158 @@
+/*
+ * Copyright (C) 2011 The CyanogenMod Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.cyanogenmod.settings.device;
+
+import android.app.ActionBar;
+import android.app.ActionBar.Tab;
+import android.app.ActionBar.TabListener;
+import android.app.Activity;
+import android.app.Fragment;
+import android.app.FragmentManager;
+import android.app.FragmentTransaction;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.ServiceConnection;
+import android.os.Bundle;
+import android.os.IBinder;
+import android.support.v13.app.FragmentPagerAdapter;
+import android.support.v4.app.FragmentActivity;
+import android.support.v4.view.ViewPager;
+
+import com.cyanogenmod.settings.device.R;
+
+import java.util.ArrayList;
+
+public class DeviceSettings extends Activity {
+
+    public static final String SHARED_PREFERENCES_BASENAME = "com.cyanogenmod.settings.device";
+    public static final String ACTION_UPDATE_PREFERENCES = "com.cyanogenmod.settings.device.UPDATE";
+    public static final String KEY_GAMMA_TUNING = "gamma_tuning";
+    public static final String KEY_CATEGORY_RADIO = "category_radio";
+    public static final String KEY_HSPA = "hspa";
+
+    ViewPager mViewPager;
+    TabsAdapter mTabsAdapter;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        mViewPager = new ViewPager(this);
+        mViewPager.setId(R.id.viewPager);
+        setContentView(mViewPager);
+
+        final ActionBar bar = getActionBar();
+        bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
+        bar.setDisplayOptions(ActionBar.DISPLAY_SHOW_TITLE, ActionBar.DISPLAY_SHOW_TITLE);
+        bar.setTitle(R.string.app_name);
+
+        mTabsAdapter = new TabsAdapter(this, mViewPager);
+        mTabsAdapter.addTab(bar.newTab().setText(R.string.display_title),
+                DisplayFragmentActivity.class, null);
+        mTabsAdapter.addTab(bar.newTab().setText(R.string.general_title),
+                GeneralFragmentActivity.class, null);
+
+        if (savedInstanceState != null) {
+            bar.setSelectedNavigationItem(savedInstanceState.getInt("tab", 0));
+        }
+    }
+
+    @Override
+    protected void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+        outState.putInt("tab", getActionBar().getSelectedNavigationIndex());
+    }
+
+    public static class TabsAdapter extends FragmentPagerAdapter
+            implements ActionBar.TabListener, ViewPager.OnPageChangeListener {
+        private final Context mContext;
+        private final ActionBar mActionBar;
+        private final ViewPager mViewPager;
+        private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
+
+        static final class TabInfo {
+            private final Class<?> clss;
+            private final Bundle args;
+
+            TabInfo(Class<?> _class, Bundle _args) {
+                clss = _class;
+                args = _args;
+            }
+        }
+
+        public TabsAdapter(Activity activity, ViewPager pager) {
+            super(activity.getFragmentManager());
+            mContext = activity;
+            mActionBar = activity.getActionBar();
+            mViewPager = pager;
+            mViewPager.setAdapter(this);
+            mViewPager.setOnPageChangeListener(this);
+        }
+
+        public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) {
+            TabInfo info = new TabInfo(clss, args);
+            tab.setTag(info);
+            tab.setTabListener(this);
+            mTabs.add(info);
+            mActionBar.addTab(tab);
+            notifyDataSetChanged();
+        }
+
+        @Override
+        public int getCount() {
+            return mTabs.size();
+        }
+
+        @Override
+        public Fragment getItem(int position) {
+            TabInfo info = mTabs.get(position);
+            return Fragment.instantiate(mContext, info.clss.getName(), info.args);
+        }
+
+        @Override
+        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
+        }
+
+        @Override
+        public void onPageSelected(int position) {
+            mActionBar.setSelectedNavigationItem(position);
+        }
+
+        @Override
+        public void onPageScrollStateChanged(int state) {
+        }
+
+        @Override
+        public void onTabSelected(Tab tab, FragmentTransaction ft) {
+            Object tag = tab.getTag();
+            for (int i=0; i<mTabs.size(); i++) {
+                if (mTabs.get(i) == tag) {
+                    mViewPager.setCurrentItem(i);
+                }
+            }
+        }
+
+        @Override
+        public void onTabUnselected(Tab tab, FragmentTransaction ft) {
+        }
+
+        @Override
+        public void onTabReselected(Tab tab, FragmentTransaction ft) {
+        }
+    }
+}
diff --git a/GNexusParts/src/com/cyanogenmod/settings/device/DisplayFragmentActivity.java b/GNexusParts/src/com/cyanogenmod/settings/device/DisplayFragmentActivity.java
new file mode 100755
index 0000000..607339e
--- /dev/null
+++ b/GNexusParts/src/com/cyanogenmod/settings/device/DisplayFragmentActivity.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2011 The CyanogenMod Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.cyanogenmod.settings.device;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.os.Bundle;
+import android.preference.CheckBoxPreference;
+import android.preference.Preference;
+import android.preference.PreferenceActivity;
+import android.preference.PreferenceFragment;
+import android.preference.PreferenceManager;
+import android.preference.PreferenceScreen;
+import android.util.Log;
+
+import com.cyanogenmod.settings.device.R;
+
+public class DisplayFragmentActivity extends PreferenceFragment {
+
+    private GammaTuningPreference mGammaTuning;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        addPreferencesFromResource(R.xml.display_preferences);
+
+        mGammaTuning = (GammaTuningPreference) findPreference(DeviceSettings.KEY_GAMMA_TUNING);
+        mGammaTuning.setEnabled(GammaTuningPreference.isSupported());
+    }
+
+}
diff --git a/GNexusParts/src/com/cyanogenmod/settings/device/GammaTuningPreference.java b/GNexusParts/src/com/cyanogenmod/settings/device/GammaTuningPreference.java
new file mode 100644
index 0000000..bfbc62e
--- /dev/null
+++ b/GNexusParts/src/com/cyanogenmod/settings/device/GammaTuningPreference.java
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2011 The CyanogenMod Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.cyanogenmod.settings.device;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.content.SharedPreferences.Editor;
+import android.preference.DialogPreference;
+import android.preference.PreferenceManager;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.SeekBar;
+import android.widget.TextView;
+
+/**
+ * Special preference type that allows configuration of both the ring volume and
+ * notification volume.
+ */
+public class GammaTuningPreference extends DialogPreference {
+
+    private static final String TAG = "GAMMA...";
+
+    enum Colors {
+        RED, GREEN, BLUE
+    };
+
+    private static final int[] SEEKBAR_ID = new int[] {
+            R.id.gamma_red_seekbar, R.id.gamma_green_seekbar, R.id.gamma_blue_seekbar
+    };
+
+    private static final int[] VALUE_DISPLAY_ID = new int[] {
+            R.id.gamma_red_value, R.id.gamma_green_value, R.id.gamma_blue_value
+    };
+
+    private static final String[] FILE_PATH = new String[] {
+            "/sys/class/misc/samoled_color/red_v1_offset",
+            "/sys/class/misc/samoled_color/green_v1_offset",
+            "/sys/class/misc/samoled_color/blue_v1_offset"
+    };
+
+    private GammaSeekBar mSeekBars[] = new GammaSeekBar[3];
+
+    private static final int MAX_VALUE = 80;
+
+    private static final int OFFSET_VALUE = 0;
+
+    // Track instances to know when to restore original color
+    // (when the orientation changes, a new dialog is created before the old one
+    // is destroyed)
+    private static int sInstances = 0;
+
+    public GammaTuningPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+
+        setDialogLayoutResource(R.layout.preference_dialog_gamma_tuning);
+    }
+
+    @Override
+    protected void onBindDialogView(View view) {
+        super.onBindDialogView(view);
+
+        sInstances++;
+
+        for (int i = 0; i < SEEKBAR_ID.length; i++) {
+            SeekBar seekBar = (SeekBar) view.findViewById(SEEKBAR_ID[i]);
+            TextView valueDisplay = (TextView) view.findViewById(VALUE_DISPLAY_ID[i]);
+            mSeekBars[i] = new GammaSeekBar(seekBar, valueDisplay, FILE_PATH[i]);
+        }
+    }
+
+    @Override
+    protected void onDialogClosed(boolean positiveResult) {
+        super.onDialogClosed(positiveResult);
+
+        sInstances--;
+
+        if (positiveResult) {
+            for (GammaSeekBar csb : mSeekBars) {
+                csb.save();
+            }
+        } else if (sInstances == 0) {
+            for (GammaSeekBar csb : mSeekBars) {
+                csb.reset();
+            }
+        }
+    }
+
+    /**
+     * Restore screen color tuning from SharedPreferences. (Write to kernel.)
+     * 
+     * @param context The context to read the SharedPreferences from
+     */
+    public static void restore(Context context) {
+        if (!isSupported()) {
+            return;
+        }
+
+        SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(context);
+        for (String filePath : FILE_PATH) {
+            String sDefaultValue = Utils.readOneLine(filePath);
+            int iValue = sharedPrefs.getInt(filePath, Integer.valueOf(sDefaultValue));
+            Utils.writeValue(filePath, String.valueOf((long) iValue));
+        }
+    }
+
+    /**
+     * Check whether the running kernel supports color tuning or not.
+     * 
+     * @return Whether color tuning is supported or not
+     */
+    public static boolean isSupported() {
+        boolean supported = true;
+        for (String filePath : FILE_PATH) {
+            if (!Utils.fileExists(filePath)) {
+                supported = false;
+            }
+        }
+
+        return supported;
+    }
+
+    class GammaSeekBar implements SeekBar.OnSeekBarChangeListener {
+
+        private String mFilePath;
+
+        private int mOriginal;
+
+        private SeekBar mSeekBar;
+
+        private TextView mValueDisplay;
+
+        public GammaSeekBar(SeekBar seekBar, TextView valueDisplay, String filePath) {
+            int iValue;
+
+            mSeekBar = seekBar;
+            mValueDisplay = valueDisplay;
+            mFilePath = filePath;
+
+            SharedPreferences sharedPreferences = getSharedPreferences();
+
+            // Read original value
+            if (Utils.fileExists(mFilePath)) {
+                String sDefaultValue = Utils.readOneLine(mFilePath);
+                iValue = Integer.valueOf(sDefaultValue);
+            } else {
+                iValue = MAX_VALUE - OFFSET_VALUE;
+            }
+            mOriginal = iValue;
+
+            mSeekBar.setMax(MAX_VALUE);
+            reset();
+            mSeekBar.setOnSeekBarChangeListener(this);
+        }
+
+        public void reset() {
+            int iValue;
+
+            iValue = mOriginal + OFFSET_VALUE;
+            mSeekBar.setProgress(iValue);
+            updateValue(mOriginal);
+        }
+
+        public void save() {
+            int iValue;
+
+            iValue = mSeekBar.getProgress() - OFFSET_VALUE;
+            Editor editor = getEditor();
+            editor.putInt(mFilePath, iValue);
+            editor.commit();
+        }
+
+        @Override
+        public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
+            int iValue;
+
+            iValue = progress - OFFSET_VALUE;
+            Utils.writeValue(mFilePath, String.valueOf((long) iValue));
+            updateValue(iValue);
+        }
+
+        @Override
+        public void onStartTrackingTouch(SeekBar seekBar) {
+            // Do nothing
+        }
+
+        @Override
+        public void onStopTrackingTouch(SeekBar seekBar) {
+            // Do nothing
+        }
+
+        private void updateValue(int progress) {
+            mValueDisplay.setText(String.format("%d", (int) progress));
+        }
+
+    }
+
+}
diff --git a/GNexusParts/src/com/cyanogenmod/settings/device/GeneralFragmentActivity.java b/GNexusParts/src/com/cyanogenmod/settings/device/GeneralFragmentActivity.java
new file mode 100644
index 0000000..ca1b155
--- /dev/null
+++ b/GNexusParts/src/com/cyanogenmod/settings/device/GeneralFragmentActivity.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2011 The CyanogenMod Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.cyanogenmod.settings.device;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.os.Bundle;
+import android.preference.CheckBoxPreference;
+import android.preference.ListPreference;
+import android.preference.Preference;
+import android.preference.PreferenceActivity;
+import android.preference.PreferenceFragment;
+import android.preference.PreferenceManager;
+import android.preference.PreferenceScreen;
+import android.util.Log;
+
+import com.cyanogenmod.settings.device.R;
+
+public class GeneralFragmentActivity extends PreferenceFragment {
+
+    private static final String PREF_ENABLED = "1";
+    private static final String TAG = "GNexusParts_General";
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        addPreferencesFromResource(R.xml.general_preferences);
+
+        PreferenceScreen prefSet = getPreferenceScreen();
+
+    }
+
+    @Override
+    public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen, Preference preference) {
+
+        String boxValue;
+        String key = preference.getKey();
+
+        Log.w(TAG, "key: " + key);
+
+        return true;
+    }
+
+    public static boolean isSupported(String FILE) {
+        return Utils.fileExists(FILE);
+    }
+
+    public static void restore(Context context) {
+        SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(context);
+    }
+}
diff --git a/GNexusParts/src/com/cyanogenmod/settings/device/Hspa.java b/GNexusParts/src/com/cyanogenmod/settings/device/Hspa.java
new file mode 100644
index 0000000..cc47307
--- /dev/null
+++ b/GNexusParts/src/com/cyanogenmod/settings/device/Hspa.java
@@ -0,0 +1,57 @@
+package com.cyanogenmod.settings.device;
+
+import android.content.Context;
+import android.content.Intent;
+import android.content.SharedPreferences;
+import android.os.SystemProperties;
+import android.preference.Preference;
+import android.preference.Preference.OnPreferenceChangeListener;
+import android.preference.PreferenceManager;
+
+public class Hspa implements OnPreferenceChangeListener {
+
+    private static final String APK_FILE = "/system/app/SamsungServiceMode.apk";
+    private static final String HSPA_PROP = "ro.gnexusparts.rild.hspa";
+    private static final String HSPA_PROP_ENABLED = "1";
+
+    private Context mCtx;
+
+    public Hspa(Context context) {
+        mCtx = context;
+    }
+
+    public static boolean isSupported() {
+        String mHspa = SystemProperties.get(HSPA_PROP,"0");
+        if (mHspa.equals(HSPA_PROP_ENABLED)) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * Restore HSPA setting from SharedPreferences. (Write to kernel.)
+     * @param context       The context to read the SharedPreferences from
+     */
+    public static void restore(Context context) {
+        if (!isSupported()) {
+            return;
+        }
+
+        SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(context);
+        sendIntent(context, sharedPrefs.getString(DeviceSettings.KEY_HSPA, "23"));
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        sendIntent(mCtx, (String) newValue);
+        return true;
+    }
+
+    private static void sendIntent(Context context, String value) {
+        Intent i = new Intent("com.cyanogenmod.SamsungServiceMode.EXECUTE");
+        i.putExtra("sub_type", 20); // HSPA Setting
+        i.putExtra("data", value);
+        context.sendBroadcast(i);
+    }
+}
diff --git a/GNexusParts/src/com/cyanogenmod/settings/device/Startup.java b/GNexusParts/src/com/cyanogenmod/settings/device/Startup.java
new file mode 100644
index 0000000..82d90b7
--- /dev/null
+++ b/GNexusParts/src/com/cyanogenmod/settings/device/Startup.java
@@ -0,0 +1,17 @@
+package com.cyanogenmod.settings.device;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+
+public class Startup extends BroadcastReceiver {
+
+    @Override
+    public void onReceive(final Context context, final Intent bootintent) {
+        GammaTuningPreference.restore(context);
+        GeneralFragmentActivity.restore(context);
+        if (Hspa.isSupported()) {
+            Hspa.restore(context);
+        }
+    }
+}
diff --git a/GNexusParts/src/com/cyanogenmod/settings/device/Utils.java b/GNexusParts/src/com/cyanogenmod/settings/device/Utils.java
new file mode 100644
index 0000000..dbf2947
--- /dev/null
+++ b/GNexusParts/src/com/cyanogenmod/settings/device/Utils.java
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2011 The CyanogenMod Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.cyanogenmod.settings.device;
+
+import android.util.Log;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.SyncFailedException;
+
+public class Utils {
+    private static final String TAG = "GNexusParts_Utils";
+    private static final String TAG_READ = "GNexusParts_Utils_Read";
+    private static final String TAG_WRITE = "GNexusParts_Utils_Write";
+
+    /**
+     * Write a string value to the specified file.
+     * 
+     * @param filename The filename
+     * @param value The value
+     */
+    public static void writeValue(String filename, String value) {
+        FileOutputStream fos = null;
+        try {
+            fos = new FileOutputStream(new File(filename), false);
+            fos.write(value.getBytes());
+            fos.flush();
+            // fos.getFD().sync();
+        } catch (FileNotFoundException ex) {
+            Log.w(TAG, "file " + filename + " not found: " + ex);
+        } catch (SyncFailedException ex) {
+            Log.w(TAG, "file " + filename + " sync failed: " + ex);
+        } catch (IOException ex) {
+            Log.w(TAG, "IOException trying to sync " + filename + ": " + ex);
+        } catch (RuntimeException ex) {
+            Log.w(TAG, "exception while syncing file: ", ex);
+        } finally {
+            if (fos != null) {
+                try {
+                    Log.w(TAG_WRITE, "file " + filename + ": " + value);
+                    fos.close();
+                } catch (IOException ex) {
+                    Log.w(TAG, "IOException while closing synced file: ", ex);
+                } catch (RuntimeException ex) {
+                    Log.w(TAG, "exception while closing file: ", ex);
+                }
+            }
+        }
+
+    }
+
+    /**
+     * Write a string value to the specified file.
+     * 
+     * @param filename The filename
+     * @param value The value
+     */
+    public static void writeValue(String filename, Boolean value) {
+        FileOutputStream fos = null;
+        String sEnvia;
+        try {
+            fos = new FileOutputStream(new File(filename), false);
+            if (value)
+                sEnvia = "1";
+            else
+                sEnvia = "0";
+            fos.write(sEnvia.getBytes());
+            fos.flush();
+            // fos.getFD().sync();
+        } catch (FileNotFoundException ex) {
+            Log.w(TAG, "file " + filename + " not found: " + ex);
+        } catch (SyncFailedException ex) {
+            Log.w(TAG, "file " + filename + " sync failed: " + ex);
+        } catch (IOException ex) {
+            Log.w(TAG, "IOException trying to sync " + filename + ": " + ex);
+        } catch (RuntimeException ex) {
+            Log.w(TAG, "exception while syncing file: ", ex);
+        } finally {
+            if (fos != null) {
+                try {
+                    Log.w(TAG_WRITE, "file " + filename + ": " + value);
+                    fos.close();
+                } catch (IOException ex) {
+                    Log.w(TAG, "IOException while closing synced file: ", ex);
+                } catch (RuntimeException ex) {
+                    Log.w(TAG, "exception while closing file: ", ex);
+                }
+            }
+        }
+    }
+
+    /**
+     * Write the "color value" to the specified file. The value is scaled from
+     * an integer to an unsigned integer by multiplying by 2.
+     * 
+     * @param filename The filename
+     * @param value The value of max value Integer.MAX
+     */
+    public static void writeColor(String filename, int value) {
+        writeValue(filename, String.valueOf((long) value * 2));
+    }
+
+    /**
+     * Check if the specified file exists.
+     * 
+     * @param filename The filename
+     * @return Whether the file exists or not
+     */
+    public static boolean fileExists(String filename) {
+        return new File(filename).exists();
+    }
+
+    // Read value from sysfs interface
+    public static String readOneLine(String sFile) {
+        BufferedReader brBuffer;
+        String sLine = null;
+
+        try {
+            brBuffer = new BufferedReader(new FileReader(sFile), 512);
+            try {
+                sLine = brBuffer.readLine();
+            } finally {
+                Log.w(TAG_READ, "file " + sFile + ": " + sLine);
+                brBuffer.close();
+            }
+        } catch (Exception e) {
+            Log.e(TAG_READ, "IO Exception when reading /sys/ file", e);
+        }
+        return sLine;
+    }
+}